Means for receiving intelligence communicated by electric waves.



No. 877,451. PATENTED JAN. 21, 1908.

G. w. PIGKARD. MEANS FOR RECEIVING INTELLIGENCE GOMMUNIGATED BY ELECTRICWAVES.

APPLICATION FILED NOV.12. 1907.

1 I i" I M] all v MW W UNITED STATES PATENTTOFFIOE.

' GREENLEAF 'llITTIEB. PIOKARD, OF AMESBURY, MASSACHUSETTS.

MEANS FOR RECEIVING- INTELLIGEN'CE CONEM'UNICATED BY ELECTRIC WAVES.

Specification of .Letters Patent. I

, Patented JaIi. 21,1908.

Original application filed Align s t 30. 1906. Serial No. 332,697.Divided and application filed November 8. 1906' Serial No. 342.465.

Again divided and this application filed November 12, 1907. Serial 1c.4.01.856.

To all whom it may concern:

Be it known that I, GREENLEAF Wnrr'rrnn PICKARD, a citizen of the UnitedStates of Amer ca, and a resident of the town of Amesbury, State ofMassachusetts, have lnvented certain new and useful Imprpvements 1nMeans for Recelvlng Intelligence Communivcated by Electric Waves, theprinciples of which are set forth in the following specification andaccompanying drawing, which dis-3 closes the form of the invention which.lnow consider to be the/best of the various forms in which theprinciples of the invention may be embodied. v

This app'licaticm is a division of my appli cation Serial Number342,465,1iled Nov. 8, 1906, which was a division ol" my applicationSerial Number 332,697, filed-Aug 3 0, 1906, and granted Nov 20, 1906 asPatent No. 836,531 5' This invention relates to means for receivingintelligence Communicated by electric waves The object of the inventionis to provide a commercially usefulmeans for operating a device fortranslating the commu'nlcatlons into intelligible form, exclusively bythe energy of the oscillatory currents generated by the receipt of thewaves. T 0 this end the object is to practically convert the receivedoscillations into a'form suitable for operating anindicating device,such for example as a telephone receiver, without the use of anyauxiliary energy, and without resistance due to conductor-attenuation orimperfect contact.

. Of the drawings, Figure tie adiagrammatic illustration of awellknownform of wireless telegraph receiving station apparatus, thisbeing the apparatus with which the invention has been actually used.Figs. 2

and 3 are a side elevation and section respectively of the presentpreferred embodiment of the detector employed in the invention in itspresent most elhcient form, Fig. 3 being a slightly modified form.

In Fig. 1 the general arrangement is the well-known loop form ofwave-interceptor A, A .operatively provided with the usual 'a'djustablecapacity C, inductance L ,adjustable in both the wave-intercepter andoscillationreceiving circuits, the inductance-L, adjustable in thewave-intercepter circuit, and the connection of the latter circuit toground at G.

O In Fig. 1, the circuit L, T, J, CT, L receives the oscillationsgenerated in the waveintercepting loop A, A, the inductance L beingadjustable in the oscillation circuit which is well adapted for use withthe oscillation receiver or detector of this invention, as it includesthe adjust-able condenser C, andthe indicating device T in shunt to thiscondenser. The device is preferably a telephone receiver and may be anyother form of device such as a sensitive galvanometer which willinilicate an abrupt flow of direct current. The receiver or detectorshould in use be maintained in good electrical connection in theoscillation circuit, and the contactjunction '1 J should be asubstantially perfect electrical contact. The lead to the shuntconnectedcondenser C and the telephone T is taken from the lower end of theinductance L, so that the telephone and its parallel connectedcondenserare in series between the detector and a part of the inductance L whichis of lower potential with respect to the ground.

The receiver-or detector of this invention, roughly indicated at T J inFig. 1. is shown detail in Fig. 2. I are secured an angular metalsupport 2 and a metal plate 3, provided with binding posts 4, 5 for ,theleads of the oscillating circuit of Fig. 1'. ,One element of thedetector is the chuck'which is removably screwed into the plate 3 bythe'part 6. This chuck To a wooden base consists of apiece of metal M towhich is material N upon a metallic surface, or otherwise; and as shownin Fig. 3, it is s'u'llicient to place the material N in a liquefiedmass of fusible metal F Min "a chuck cup 18, provided with a screw 17,so that when the metal F M cools and solidifiesf the material- N will befirmly embedded in, and in good electrical and large-areaed contact withthe metal F M. The operative contact-junction (T J of Fig. 1 is locatedatthe lower end of the than that of the contact between N and Mindicating device.

eily wit '1 the member N.

P. The sleeve 7 can slide along the metallic projection 8 which dependsfrom the metallic all 9, the ball formin a ball-and-socket universaljoint with the part 10 of thin metal, which is stamped to shapeandsecured to the metallic support ,2 so as to complete the circuit. Themember 7 of the receiver may be of an conductor which cooperates prop-The member N may be the element silicon, which appears to be most usefuleither in the massive amorphous or graphitic solid form; or it may be asuitable equivalent which accomplishes the objects of the invention, i.e., a conductor within the scope of the invention which possesses highresistivity and which when operatively in substantially perfectelectrical contact with the other conductor, as 7, operates incooperation therewith to produce a direct current suitable for operatingthe When ,the member 7 is metallic, as of copper in accordance with thisdisclosure, and therefore has low resistivity, there is a verysubstantial difference in the degree of resistivity possessed by the twoconductors. When the member N has high thermoelectromotive power incooperation with the member 7, in addition to high resistivity, or whenthere is a substantial difference in the resistivity of the twoconductors, a considerable part of the energy of the receivedoscillations is concentrated in the form of Joulean heat, at the contactjunction, where it may be converted into a direct .current owing to thecooperative there mo-electromotive power of tlietwo conductors.conductors 7 and. N should be a substantially perfect electricalcontact, and this is secured y the spring 11, which presses the twoconductors together with suflicient force to exclude substantially allcontact resistance and action of a loose -contact or coherer naturearising from the resistance of an imperfect contact, such as to causethe contact to be a substantially perfect one.- Such a perfect contactnot only accomplishes the objects of'the invention, but avoids theuncommercial instability of imperfect contacts. The spring 11 alsovserves to make good contact between thepart 7' and the pressure toinsure a substantially perfect contact. The spring 11 however,cooperatively with the movable part 8, permits the selection by manualadjustment of difl'erent locations of the contact T J, owing, inthis Thejunction between the massive disclosure, to inequalities of differentparts of the operating surface of part N, whereby the pressure of thespring is slightly varied within the limits of perfect contact pressure,so as to slightly vary the area of electrical contact and thesensitiveness of operation under different external conditions of use.In no case, however, is it necessary to continuouslymov'e either 7 or Nwith respect to each other during operation. The device is mostefficient in the form shown, as to-the lower end of part 7 having asubstantial roundedsurface in physical contact of considerable. areawith part N, but having an extremely small electrical contact therewith.In no case need either member 7' or N possess such attenuation as mightthereby generate heat.

'1 am aware of devices in the prior art which employconductor-attenuation as an essential means of generating heat, and ofthose which employ the resistance of an imperfect contact as anessential means of generating heat. In this invention however, it isunnecessary to employ either of such means, the action being eflicientin all cases of pairs of conductors included within the invention whichcooperatively have highresistivity and are in small-aread vsubstantially g perfect contact with each other.

In order to obtain the best results, the' 1 above specification shouldbe carefully followed. So far I havebeen able to convert upward of tenpercent. of the energy of the oscillations into direct current energy..The device is therefore an electricalconverter or rectifier. In thepreferred form: of this invention the action due to the inherentproperties of the silicon member or its equivalent is of extraordinaryvigor, as is indicated by the fact that the only energy employed tocommercially operate the telephone T is that of the receivedoscillations. All resistancevarying action should be reduced to aminimum, as by employing the conductors in substantially massive formand inlsubstantially perfect contact with each other, because the energyof the oscillations should not be wastedwithout contributingsubstantially to effective action.

The remarkable 'fact that the telephone can be operated in a commercialmanner, solely by the converted ener of the received oscillations, isexplainefb ment that that feeble energy which is re-,

y the stateceived at the ordinary commercial wireless telegraph stationis amply suflicient to operate a sensitive receiving instrument,provided that the translation of this ener into the form of a directcurrent is' efiicient y. ac-

comphshed. It is, ofcourse, necessary in commercial work to effect thisconversion,

because there is no known indicating means which'can be sensiblyaffected by the received energy of commercial long-distance wirelesstelegraphy when in the form of high frequency oscillations,notwithstanding the fact that a sensitive telephone may, as anexperimental feat, be slightly'affected by the oscillations emittedfrom'a nearby or very powerfulsending station.

'wireless communication is, at the minimum,

of the order of magnitude of one-thousandth of an erg-per dot.. 'l'he.efficiency of the apparatus of this invention, as demonstrated by trialunder commercial conditions, is upwards of ten per cent. There is thusample margin for commercialoperativeness for the least sensitive form ofthis invention in the case of the present longest distance wirelesstelegraphy. 1 4

The speed of reception with this invention is unlimited, since it is notonly self-restoring to its sensitive state, but this restoration ispractically instantaneous because, so far as 4 the thermoelectromotlveactlon is concerned,

the small quantity of heat which is'generated bythe receivedoscillations comprising a signal is rapidly conducted away, partly by 30thermal conduction to the metal portion 7, and the remainder b theconversion into an electric current whlch finally expends its energy inthe indicating device.

The advantages of the new detector are as follows. It fulfils all reuirements of commercial wireless telegrap y as to sensitiveness, speed,stabilityand freedom from delicate adjustments. I have found that thecontinued sensitiveness of the detector is in nowise impaired by severestatic discharges. It is also simple and cheap in construction.

It is not affected by changes in atmospheric temperature or humidity.Itssensitiveness so far has not beeniimpaired by continuous andcontinued use. Any portion of any 'oneof the classes of'material havingthe inherent properties of the conductors included within thisinvention, makes an operative .con-

tact with another suitable conductor if that contact vbe substantially,perfect. This invention requires no auxiliary source of heat as has beennecessary with previous converters designed for,high frequencyoscillations. It is an important practicalas well as commercialadvantage of this invention that it essentially dispenses with auxiliaryI sources of energy, in that such sources, such as batteries and therequisite accompanying potentiometers, areexpensive and require fre uentreplacement [here is apparently no imit to the operative life of thedetectors included in this invention.

term here meaning. a non-attenuated, non- 'mass.

comminuted solid having a substantially uniform chemicalcompositionthroughout the This word massive as used in the claims, does not possessits special mineralogical meaning which may exclude either crystallineform or crystalline structure, because it here includes non-attenuated,noncomininuted solids which may have either such form or'such structure;nor does the word massive, in the claims, possess its special geologicalmeaning of homogeneity as to being destitute of structural divisionssuch as planes of stratification, because it here includesnon-attenuated, non-comminutedsolids which may have cleavage formations: The only limitations here placed on the word massive are thatthe material is not a chemical formation on a mere sur face, or aconductor attenuated for the necessary purpose of thereby obtainingnecessary heat-producing resistance, and that it is not comminuted tosuch degree as'to lose its massive character-as and for the. purposesset forth.

Y The expression substantially perfect electrical contact in the claims,means the good electrical contact for the purpose of this invention,that is to say, a contact which has substantially no contact resistance,11. 0., is not imperfect or microphonic such as might be necessarilyemployed to result in the generation of heat by means of the resistanceof an imperfect contact, or to operate by varying contact-resistance,The substantially perfect contact of this invention is characterized byconsiderable pressure suflicient toexclude -material imperfection orlooseness and substantially all contact resistance due to suchlooseness, as distinguished from the empirical or definite looseness, orcontact "resistance, necessarily employed outside of On the other hand,the two this invention. conductors of this invention are individuallyseparate, and the expression substantially resistance.

The meaning of the adjective non-metal he as used herein, is thecommonly accepted one which excludes all metals, alloys or.

chemical mixtures of one metal with another,

and-which includes all non-metal elements, and chemical compounds ofnon-metals with I metallic substances.

I claim:

. 1. Means for receiving. intelligence communicated byelectromagneticwaves, which comprises two substantially massive'indiyidual electrical conductors operatively in substantially perfectcontact with .each

' other, said. conductors having different dehighresistivity,-at leastone of which conductors possesses high, resistivity; incombination witha spring which operatively holds the said conductors in substantiallyperfect small-areaed electrical contact with each other; and a freelymovable, non-threaded support for said spring to permit a variation ofcontact pressure within wide limits of substantially erfect contactpressure, and thereby slig tly vary the area of the minute electricalcontact. 7

3. Means for receiving intelligence communicated by electromagneticWaves, which comprises two substantially massive individual conductorsoperatively in small-areaed substantially perfect contact with eachother, and having different degrees of resistivity and cooperativelyhaving high resist-- ivity, at least one of said conductors havinghighresistivity; in combination with a mass of good conducting materialhaving a broad surface of intimate contact, relative .to saidsmall-areaed contact, with said high resistance conductor.

'4. Means for receiving intelligence com municated by electromagneticwaves, which comprises a substantially massive conducting solid havinglow resistivity, and a substantially massive non-metallic solid havinghigh resistivity and also thermoelectromoseparate, but operativelyconnected tocontact v 5. Means for receiving intelligence communicatedby electromagnetic waves, which comprises two substantially massiveindividual conducting solids, one of which has low resistivity, and theother of which has 7 high resistivity and alsothermoelectrohiotivepower; said conductors being operatively connected 'tOgGthGIf'iH'substantially perfect electrical contact.

6. Means for receiving intelligence communicated by electromagneticwaves, which comprises a substantially massive l'ow resistance metalhcmember, and a separate substantiallymassive conducting solid having highresistivity; said members being con nected together in substantiallyperfect electrical contact;'said member which has h gh resistivityhaving also thermoelectromotive t e power said conductors beingindividu-. iv

trica trical currents into direct currents, which comprises asubstantially massive low resistance conducting solid in substantiallyperfectelectrical contact but not integral with a substantlally massiveconducting solid having high resistivity and also thermoelectromo-- t vepower.

8. Means for receiving intelligence communicated by electromagneticwaves, which comprises two substantially massive individual electr callyconduct ng solids cooperat1vely hav1ng high resistivity and alsothermo-electromotive power'; in combination with means for holding saidconductors together in substantially perfect contact.

9. Means for receiving intelligence communicated by electromagneticwaves, which com rises two substantially massive electrica 1y conductingsolids which are individually separate, but 006 eratively connectedtogether in substantia ly perfect electrical contact, said conductor'scooperativelyhaw ing high resistivity and also cooperatively possessingthermoelectromotive ower.

10. Means for receiving inte 'gence communicated by electromagneticwaves, which com rises two substantially massive electrica ly conductingsolids, which are individually separate, but operatively connectedtogether in small-areaed substantially perfect electrical contact, saidconductors cooperatively having high resistivity and also cooperativelypossessing thermoelectromotive power.

- 11 Means for receiving intelligence com- 'municated by electroma neticwaves, which comprises two substantla ly massive electr1c-' allyconducting solids which are individually separateybut cooperativelyconnected together in siuall-areaed substantially perfect electricalcontact, said conductors cooperatively possessing thermoelectromotivepower, and having substantially different degrees of resistivity, atleast oneJof the conductors having 'high'resistivit I 12. Means forrecelving intelligence com municated by electromagnetic waves, whichcomprises two substantially massive electrically conducting solids whichare individually separate, but operativel connected together insubstantially pe ect'electrical contact, said conductors cooperativelhaving high resistivity and also thermoe ectromotive power, and theindividual conductors having substantially different degrees ofresistivity. o

13. Means for recelving intelligence com-- municated by electromagneticwaves, which complrises two substantially massive elecy conductingsolids which are individually separate, but operatively connectedtogether in small-areaed substantially perfect electrical contact, saidconductors having substantially different degrees of resistivity, andcoo eratively having high resistivity.

14. cans for receiving intelligence com- Inunicated by electromagiieticwaves, which comprises two substantia y massive electrically conductingsolids which are individually separate, but'o eratively connectedtogether in substantialy perfect electrical contact,

.said conductors cooperatively having high resistivity, at least one ofthem having high resistivity; a mass of fusible good conducting materialin which the "high resistance conductor isembedded; and a receptacle forthe fusible conductor.

15. Means for receiving intelligence communicated by electromagneticwaves, which comprises two substantially massive individual electricalconductors of difierent degrees of resistivity and cooperatively havinghigh resistivity, at least one of said conductors possessing highresistivity; in combination com rises two individualmassive electricalcom uctors of different degrees of resistivity and cooperatively havinghigh resistivity, at

least one of which conductors has high resistivity; in combination witha supporting member having a telescopic joint with one of saidconductors; a spring operatively located. within the telescopic joint tohold the two conductors in substantially perfect contact .with eachother; and means to permit the manual alteration of the location of the("ontact junction of the two conductors.

- GREENLEAI! Wlll'll'llllll l'lhKMtlL Witnesses: 1

EDWARD I-I. RowELL, MYRA S. RowELL.

